Adhesion promoter intended for application to a thermoplastic elastomer polymer substrate and corresponding processes for surface treatment and adhesive assembly

ABSTRACT

Use, as adhesion promoter intended for application to the surface of a substrate S1 made of thermoplastic elastomer polymer TPE which comprises a chain formed of an alteration of hard segments and of soft segments, for the purpose of the adhesive assembly of the said substrate S1 with another substrate S2, of at least one solvent of the hard segments and/or of the soft segments of the said thermoplastic elastomer polymer TPE.

This application claims benefit, under U.S.C. §119 or §365 of FrenchApplication Number FR 06.50220, filed Jan. 23, 2006; U.S. 60/784,313,filed Mar. 21, 2006; and PCT/FR2007/050680 filed Jan. 23, 2007.

FIELD OF THE INVENTION

The present invention relates to the adhesive assembly of a firstthermoplastic elastomer polymer substrate S1 and of a second substrateS2 which may be of any nature, for example: polymer, wood, glass,leather, paper, cardboard.

The expression “thermoplastic elastomer polymer, abbreviated to TPE” isintended to mean a block copolymer comprising alternating blocks orsegments referred to as hard or rigid and blocks or segments referred toas soft or flexible.

The principal thermoplastic elastomer polymers that may be mentioned arethose in which the soft blocks are blocks of polyether (PE) and/orpolyester (PES) and the hard blocks are blocks of polyamide (PA),polyurethane (PU) or polyester (PES), it then being possible for theTPEs to be denoted respectively TPE-A, TPE-U and TPE-E.

Although the present invention is in no way limited to TPE-As, thelatter represent a particularly preferred category. They can becategorized as polyether ester amides, for which the bonds between thePA blocks and the PE blocks are ester bonds, and polyester amides, forwhich the bonds between the PA blocks and the PE blocks are amide bonds.By way of examples of TPE-A, mention may be made of those sold under thetrademark PEBAX® by the company Arkema.

BACKGROUND OF THE INVENTION

Over the past few years, thermoplastic elastomer polymers, such aspolyether ester amide and polyester amide TPE-As, have been widely usedin the field of sports shoes, in particular for constituting soles ofshoes, for their good mechanical properties, in particular theirspring-back property.

In such applications, the soles of sports shoes are made of at least twolayers, often one made of TPE-A (in particular of PEBAX®) and the othermade of TPE-PU, these two layers being adhesively assembled.

In general, TPE substrates are assembled by adhesion to the othersubstrates by means of a primer and of adhesives or glues comprisingorganic solvents, also known as solvent-based primers or solvent-basedadhesives, these primers and these adhesives are generally two-componentpolyurethane adhesives. The two-component adhesives comprise a firstcomponent which is an organic resin or a mixture of organic resinscomprising functions that can react with the second (crosslinking)component consisting of an isocyanate or of a mixture of isocyanates insolution at least in an organic or pure solvent. By way of examples, theresins constituting the first component may be polyesters, acrylics orepoxy resins comprising hydroxylated, carboxylated, epoxy, amine oramide reactive functions, in solution in an organic solvent, and asecond (crosslinking) component which is a solution of isocyanate in anorganic or pure solvent.

The conventional assembly process comprises the following successivesteps:

Preparation of Substrates S1 and S2:

-   -   Cleaning: the surfaces to be bonded are cleaned, in general,        with an organic solvent, in particular methyl ethyl ketone        (abbreviated to MEK); the solvent evaporates off during drying,        thus involving waste given off into the atmosphere;    -   Application of a primer: a solvent-based two-component        polyurethane-based primer layer is applied, in general with a        brush, to the surface, of the substrates, that is to be bonded;        the whole is then placed in an oven in order to dry the primer,        this step again involving solvent emissions into the atmosphere;    -   Application of an adhesive: a layer of solvent-based or        water-based, two-component polyurethane adhesive is applied, in        general with a brush, to the substrates prepared; the whole is        placed in an oven, generating further emission of solvent into        the atmosphere when a solvent-based adhesive is used.        Assembly of Substrates S1 and S2:

The two substrates S1 and S2 that have thus been adhesive-coated areassembled and undergo a pressing operation in order to ensure theiradhesion.

During these various steps, it has been evaluated that approximately 30kg of organic solvents originating from the use of a solvent-basedprimer and of a solvent-based adhesive are emitted during the assemblyof 10 000 shoes. For this reason, it will be desirable to use primersand/or adhesives that are less polluting in order to limit the solventemissions while having multilayer structures for which the adhesionbetween the layers of substrate S1 and S2, defined above, is compatiblewith use in the field of shoe soles.

DETAILED DESCRIPTION OF THE DRAWINGS

FIGS. 1, 2 and 3 represent schematically the multilayer structure ofexample 3, example 11 and example 12, respectively.

DETAILED DESCRIPTION OF THE INVENTION

The present invention proposes to address this technical problem. Asubject of the present invention is the use of at least one adhesionpromoter which is a solvent intended for application to the surface of asubstrate S1 during a cleaning/activation step, said substrate S1 beingmade of a thermoplastic elastomer polymer TPE comprising a chain formedfrom alternating hard segments and soft segments, for the purpose of theadhesive assembly of said substrate S1 with another substrate S2. Asubject of the present invention is also a laminated product or amultilayer structure and a process comprising the application of atleast one adhesion promoter which is a solvent or a mixture of solventsto a substrate S1 of TPE type, followed by a step of coating S1 with anaqueous primer and/or an aqueous adhesive of the two-componentpolyurethane type, and then assembly of the adhesive-coated substratesS1 and S2, making it possible to obtain bonding with an effectiveadhesive strength. Prior to the adhesive-coated substrate S1 beingbrought into contact with the substrate S2, an aqueous or solvent primerand/or an aqueous or solvent adhesive will be applied to the surface ofS2 intended to be adhesive-coated and intended to be brought intocontact with S1, this surface having undergone, before adhesive-coating,cleaning or cleaning/activation depending on the nature of S2.

In the case where S2 is made of TPE, a step of cleaning/activation ofthe surface of S2 intended to be adhesive-coated is carried out, duringwhich step, as for S1, an adhesion promoter is applied, followed bycoating with an aqueous primer and/or an aqueous adhesive of thetwo-component polyurethane type.

In the case where S2 is not made of TPE, the surface of S2 intended tobe adhesive-coated will simply be cleaned with a solvent, the nature ofthe solvent and also the nature of the primer and/or of the adhesiveintended to be applied to said surface of S2 will be chosen in anappropriate manner depending on the nature of the substrate S2.

The adhesion promoter(s) is (are) advantageously chosen from solvents(i) capable of making the chains of TPE flexible and renderingaccessible the functions capable of reacting or interacting with atleast one adhesive system, which is an aqueous adhesive and/or anaqueous primer, and/or (ii) capable of providing surface swelling of theTPE substrate S1.

The adhesion promoter(s) can be incorporated into an aqueous adhesionprimer and/or into an aqueous adhesive and/or into the substrate by bulkincorporation during its transformation.

As regards the adhesion promoter(s), mention may be made of butanediolssuch as 1,3-butanediol or 1,4-butanediol, metacresol, carvacrol,glycerol, glycols, butanols such as n-butanol or isobutanol, benzylalcohol, butyl glycol, butyl diglycol and limonene, and mixturesthereof.

The adhesion promoter(s) may be functional solvents capable of reactingor interacting with at least one adhesive system which is preferably anaqueous adhesive comprising free isocyanate functions in the case of theadhesion promoter and the adhesive being brought into contact directlyin the laminated product and/or an aqueous primer comprising freeisocyanate functions in the case of the adhesion promoter and the primerbeing brought into contact directly in the laminated product. Thefunctional solvent(s) may be chosen from compounds comprising at leastone —OH, —COOH or —NH₂ function, borne by a backbone that is inparticular aliphatic, cycloaliphatic or aromatic. In particular,functional solvents that may be mentioned include thymol, carvacrol,butanols, butanediols, butyl glycol, butyl diglycol, glycerol, benzylalcohol and metacresol, and mixtures thereof.

However, if use was made of blocked isocyanate functions which would bedeblocked at the time the adhesive system was used, i.e. at the time theadhesive and/or the primer were used, this would not depart from thecontext of the invention.

The adhesion promoter(s) (i) may be cleaning solvents or functionalsolvents for the substrates S1 or S1 and S2 when the substrates are ofthe same nature, or (ii) is (are) combined with at least one cleaningsolvent or at least one functional solvent for said substrate(s).

The adhesion promoter(s) may be capable of acting under cold conditionsor under hot conditions.

The thermoplastic elastomer copolymers of the substrate S1, or even ofthe substrate S2, can be chosen from copolymers comprising soft PEblocks and comprising hard blocks chosen from polyamides PA,polyurethanes PU and polyesters, preferably copolymers comprising PEBAblocks, of polyether ester amide and polyether amide type.

By way of example of polyether block copolymers, mention may be made ofcopolymers comprising polyester blocks and polyether blocks (also calledpolyether esters), copolymers comprising polyurethane blocks andpolyether blocks (also called TPUs, the abbreviation for thermoplasticpolyurethanes) and copolymers comprising polyamide blocks and polyetherblocks (also called PEBAs according to the IUPAC).

As regards the polyether esters, these are copolymers comprisingpolyester blocks and polyether blocks. They consist of soft polyetherblocks, which are the residues of polyetherdiols, and rigid segments(polyester blocks), which result from the reaction of at least onedicarboxylic acid with at least one chain-extender short diol unit. Thepolyester blocks and the polyether blocks are linked by ester linksresulting from the reaction of the acid functions of the acid with theOH functions of the polyetherdiol. The chain-extender short diol may bechosen from the group consisting of neopentyl glycol,cyclohexanedimethanol and aliphatic glycols of formula HO(CH₂)_(n)OH inwhich n is an integer ranging from 2 to 10.

Advantageously, the diacids are aromatic dicarboxylic acids having from8 to 14 carbon atoms. Up to 50 mol % of the aromatic dicarboxylic acidmay be replaced with at least one other aromatic dicarboxylic acidhaving from 8 to 14 carbon atoms and/or up to 20 mol % may be replacedwith an aliphatic dicarboxylic acid having from 2 to 12 carbon atoms.

By way of example of aromatic dicarboxylic acids, mention may be made ofterephthalic acid, isophthalic acid, dibenzoic acid, naphthalenedicarboxylic acid, 4,4″-diphenylenedicarboxylic acid,bis(p-carboxyphenyl)methane acid, ethylenebis(p-benzoic) acid,1,4-tetramethylenebis(p-oxybenzoic) acid, ethylenebis(para-oxybenzoic)acid and 1,3-trimethylenebis(p-oxybenzoic) acid. By way of example ofglycols, mention may be made of ethylene glycol, 1,3-trimethyleneglycol, 1,4-trimethylene glycol, 1,6-hexamethylene glycol, 1,4-propyleneglycol, 1,8-octamethylene glycol, 1,10-decamethylene glycol and1,4-cyclohexylene dimethanol. The copolymers comprising polyester blocksand polyether blocks are, for example, copolymers having polyether unitsderived from polyether diols, such as polyethylene glycol (PEG),polypropylene glycol (PPG) or polytetramethylene glycol (PTMG),dicarboxylic acid units such as terephthalic acid, and glycol(ethanediol) or 1,4-butanediol units. The chainlinking of the polyethersand of the diacids forms the soft segments, whereas the chainlinking ofthe glycol or of the butanediol with the diacids forms the rigidsegments of the copolyether ester. Such copolyether esters are describedin patents EP 402 883 and EP 405 227. These polyether esters arethermoplastic elastomers. They may contain plasticizers.

As regards the TPUs, they consist of soft polyether blocks, which areresidues of polyetherdiols, and rigid blocks (polyurethanes), whichresult from the reaction of at least one diisocyanate with at least oneshort diol. The chain-extender short diol can be chosen from the glycolsmentioned above in the description of the polyether esters. Thepolyurethane blocks and the polyether blocks are linked by linksresulting from the reaction of the isocyanate functions with the OHfunctions of the polyetherdiol.

Mention may also be made of polyester urethanes, for example thosecomprising diisocyanate units, units derived from amorphous polyesterdiols and units derived from a chain-extender short diol. They maycontain plasticizers.

The copolymers comprising polyamide blocks and polyether blocks (PEBA)result from the copolycondensation of polyamide blocks having reactiveend groups with polyether blocks having reactive end groups, such as,among others:

-   -   1) polyamide blocks having diamine chain ends with        polyoxyalkylene blocks having dicarboxylic chain ends;    -   2) polyamide blocks having dicarboxylic chain ends with        polyoxyalkylene blocks with diamine chain ends obtained by        cyanoethylation and hydrogenation of aliphatic alpha,        omega-dihydroxylated polyoxyalkylene blocks, called        polyetherdiols;    -   3) polyamide blocks having dicarboxylic chain ends with        polyetherdiols, the products obtained being, in this particular        case, polyether ester amides. The copolymers of the invention        are advantageously of this type.

The polyamide blocks having dicarboxylic chain ends derive, for example,from the condensation of polyamide precursors in the presence of achain-stopper dicarboxylic acid.

The polyamide blocks having diamine chain ends derive, for example, fromthe condensation of polyamide precursors in the presence of achain-stopper diamine.

The PEBAs may also include randomly distributed units. These polymersmay be prepared by the simultaneous reaction of the polyether and of thepolyamide block precursors.

For example, a polyetherdiol, polyamide precursors and a chain-stopperdiacid may be reacted together. A polymer having essentially polyetherblocks, polyamide blocks of very variable length, but also the variousreactants that have reacted randomly, which are distributed randomlyalong the polymer chain, are obtained.

A polyether diamine, polyamide precursors and a chain-stopper diacid mayalso be reacted together. A polymer having essentially polyether blocks,polyamide blocks of very variable length, but also the various reactantsthat have reacted randomly, which are distributed randomly along thepolymer chain, are obtained.

Advantageously, three types of polyamide blocks may be used. Accordingto a first type, the polyamide blocks derive from the condensation of adicarboxylic acid and a diamine.

According to a second type, the polyamide blocks result from thecondensation of one or more alpha, omega-aminocarboxylic acids and/or ofone or more lactams having from 6 to 12 carbon atoms in the presence ofa dicarboxylic acid having from 4 to 12 carbon atoms or of a diamine.

According to a third type, the polyamide blocks result from thecondensation of at least one alpha, omega-aminocarboxylic acid (or alactam), at least one diamine and at least one dicarboxylic acid.According to a variant of this third type, the polyamide blocks resultfrom the condensation of at least two alpha, omege-aminocarboxylic acidsor of at least two lactams having from 6 to 12 carbon atoms or of alactam and of an aminocarboxylic acid not having the same number ofcarbon atoms possibly in the presence of a chain stopper.

Advantageously, the polyamide blocks of the second type are polyamide-12or polyamide-6 blocks.

By way of examples of polyamide blocks of the third type, mention may bemade of the following:

-   -   PA 6.6/Pip. 10/12 in which:    -   6.6 denotes hexamethylene adipamide (hexamethylenediamine        condensed with adipic acid) units;    -   Pip. 10 denotes units resulting from the condensation of        piperazine and of sebacic acid;    -   12 denotes units resulting from the condensation of        lauryllactam.

The proportions by weight are respectively 25 to 35/20 to 30/20 to30/the total being 80, and advantageously 30 to 35/22 to 27/22 to 27/thetotal being 80. For example, the proportions 32/24/24 result in amelting point of 122 to 137° C.

-   -   6.6/6.10/11/12 in which:    -   6.6 denotes hexamethylenediamine condensed with adipic acid;    -   6.10 denotes hexamethylenediamine condensed with sebacic acid;    -   11 denotes units resulting from the condensation of        aminoundecanoic acid;    -   12 denotes units resulting from the condensation of        lauryllactam.

The proportions by weight are respectively 10 to 20/15 to 25/10 to 20/15to 25, the total being 70, and advantageously 12 to 16/18 to 25/12 to16/18 to 25, the total being 70. For example, the proportions14/21/14/21 result in a melting point of 119 to 131° C.

The polyamide blocks are obtained in the presence of a chain-stopperdiacid or diamine, if it is desired to have polyamide blocks with acidor amine end groups. If the precursors already contain a diacid or adiamine, it is sufficient for example to use it in excess.

By way of example of aliphatic alpha, omega-aminocarboxylic acids,mention may be made of aminocaproic acid, 7-aminoheptanoic acid,11-aminoundecanoic acid and 12-aminododecanoic acid.

By way of examples of lactams, mention may be made of caprolactam,oenantholactam and lauryllactam.

By way of example of aliphatic diamines, mention may be made ofhexamethylenediamine, dodecamethylenediamine andtrimethylhexamethylenediamine.

By way of example of cycloaliphatic diacids, mention may be made of1,4-cyclohexyldicarboxylic acid.

By way of example of aliphatic diacids, mention may be made ofbutanedioic acid, adipic acid, azelaic acid, suberic acid, sebacic acidand dodecanedicarboxylic acid, dimerized fatty acids (these dimerizedfatty acids preferably have a dimer content of at least 98%; they arepreferably hydrogenated; they are sold under the brand name “Pripol” bythe company “Unichema”, or under the brand name Empol by the companyHenkel) and α,ω-polyoxyalkylene diacids.

By way of example of aromatic diacids, mention may be made ofterephthalic acid (T) and isophthalic acid (I).

The cycloaliphatic diamines may be the isomers ofbis(4-aminocyclohexyl)methane (BACM),bis(3-methyl-4-aminocyclohexyl)methane (BMACM),2,2-bis(3-methyl-4-aminocyclohexyl)propane (BMACP) andpara-aminodicyclohexylmethane (PACM). Other diamines commonly used maybe isophoronediamine (IPDA), 2,6-bis(aminomethyl)norbornane (BAMN) andpiperazine.

The polyether blocks may represent 5% to 85% by weight of the copolymercomprising polyamide and polyether blocks. The polyether blocks consistof alkylene oxide units. These units may, for example, be ethylene oxideunits, propylene oxide units or tetrahydrofuran units (which lead topolytetramethylene glycol chain linkages). Thus, PEG blocks, i.e. thoseconsisting of ethylene oxide units, PPG blocks, i.e. those consisting ofpropylene oxide units, poly(trimethylene ether glycol) units (suchcopolymers with poly(trimethylene ether) blocks are described in U.S.Pat. No. 6,590,065) and PTMG blocks, i.e. those consisting oftetramethylene glycol units, also called polytetrahydrofuran, are used.Advantageously, PEG blocks or blocks obtained by oxyethylation ofbisphenols, such as for example bisphenol A, are used. The latterproducts are described in patent EP 613 919.

The polyether blocks may also consist of ethoxylated primary amines. Itis also advantageous to use these blocks. By way of example ofethoxylated primary amines, mention may be made of the products offormula:

in which m and n are between 1 and 20 and x is between 8 and 18. Theseproducts are commercially available under the brand name NORAMOX® fromthe company CECA and under the brand name GENAMIN® from the companyCLARIANT.

The amount of polyether blocks in these copolymers comprising polyamideblocks and polyether blocks is advantageously from 10% to 70% by weightof the copolymer, and preferably from 35% to 60%.

The polyetherdiol blocks are either used as such and copolycondensedwith polyamide blocks having carboxylic end groups, or they are aminatedin order to be converted into polyether diamines and condensed withpolyamide blocks having carboxylic end groups. They may also be blendedwith polyamide precursors and a diacid chain stopper in order to makepolymers comprising polyamide blocks and polyether blocks havingrandomly distributed units.

The number-average molecular weight Mn of the polyamide blocks isbetween 500 and 10 000, and preferably between 500 and 4000, except forthe polyamide blocks of the second type. The molecular weight Mn of thepolyether blocks is between 100 and 6000, and preferably between 200 and3000.

These polymers comprising polyamide blocks and polyether blocks, whetherthey derive from the copolycondensation of polyamide blocks andpolyethers prepared beforehand, or from a one-step reaction, have, forexample, an intrinsic viscosity, measured in metacresol at 25° C. for aninitial concentration of 0.8 g/100 ml, of between 0.8 and 2.5.

As regards the preparation of the copolymers comprising polyamide blocksand polyether blocks, they may be prepared by any means allowing thepolyamide blocks and the polyether blocks to be linked together. Inpractice, essentially two processes are used, one called a two-stepprocess and the other a one-step process. In the two-step process, thepolyamide blocks are firstly produced and then, in a second step, thepolyamide blocks and the polyether blocks are linked together. In theone-step process, the polyamide precursors, the chain stopper and thepolyether are mixed together; a polymer having essentially polyetherblocks, polyamide blocks of very variable length, but also the variousreactants that have reacted randomly, which are distributed randomlyalong the polymer chain, are obtained. Regardless of whether the processis a one-step or a two-step process, it is advantageous to carry it outin the presence of a catalyst. It is possible to use the catalystsdescribed in U.S. Pat. No. 4,331,786, U.S. Pat. No. 4,115,475, U.S. Pat.No. 4,195,015, U.S. Pat. No. 4,839,441, U.S. Pat. No. 4,864,014, U.S.Pat. No. 4,230,838 and U.S. Pat. No. 4,332,920, WO 04 037898, EP1262527, EP 1270211, EP 1136512, EP 1046675, EP 1057870, EP 1155065, EP506495 and EP 504058. In the one-step process, polyamide blocks are alsoproduced; this is why it was stated at the beginning of this paragraphthat these copolymers could be prepared by any means for linking thepolyamide blocks and the polyether blocks together.

Usual polymers: those comprising PA blocks made of PA-6, made of PA-12or made of PA 6/6.6 and those comprising PTMG blocks.

As regards the substrate S2, it may be of the same nature as S1 or of adifferent nature. Mention may be made of polymers and copolymers, suchas polyolefins, polyamines, polyamides (abbreviated to PA), polyesters(abbreviated to PES), polyethers (abbreviated to PE), polyester ethers,polyimides, polyamideimides, polycarbonates, phenolic resins,crosslinked or noncrosslinked polyurethanes (abbreviated to PU), inparticular foams, polyimides, poly(ethylene/vinyl acetate)s, natural orsynthetic elastomers, such as polybutadienes, polyisoprenes,styrene-butadiene-styrene (SBS), styrene-butadiene-acrylonitrile (SBN),polyacrylonitriles, natural or synthetic fabrics, in particular fabricsmade of organic polymer fibers, such as fabrics made of polypropylene,polyethylene, polyester, polyvinyl alcohol, polyvinyl acetate, polyvinylchloride or polyaramid fibers, fabrics made of glass fibers and carbonfibers, and also materials such as leather, paper, glass, wood andcardboard. All these materials may also be in foam form when this ispossible.

In accordance with a particularly advantageous embodiment of the presentinvention, the substrate S1 is a PEBA (copolymer comprising polyamideblocks and polyether blocks) and the adhesion promoter is butanediol,advantageously as a mixture with butanol.

As regards the adhesive system, i.e. the aqueous adhesion primer and/orthe aqueous adhesive, these are two-component polyurethane-typecompositions of which:

-   -   the first component is a solution or a dispersion or an emulsion        of at least one functionalized resin in water, optionally        cosolvent-based. These functionalized resins, known to those        skilled in the art, comprise, for example, functions of the        hydroxyl, carboxyl, amine or amide type. They may be polyester        resins, acrylic resins, epoxy resins; and    -   the second component, which is added to the first component,        just before use, and which allows crosslinking of said first        component, is an isocyanate or a mixture of isocyanates.

The present invention also relates to a process for the surfacetreatment of a substrate S1 made of TPE in order to promote theattachment of an aqueous primer or of an aqueous adhesive to saidsubstrate S1 for the purpose of the adhesive assembly of said substrateS1 adhesive-coated in this way, with another substrate S2, characterizedin that an adhesion promoter is applied to the substrate S1, (i) eitherprior to the application of said aqueous primer and/or of said aqueousadhesive, as defined above, where appropriate the adhesion promoterbeing as a mixture with at least one cleaning and/or functional solventas defined above, (ii) or simultaneously with an aqueous adhesion primerand/or with an aqueous adhesive.

In accordance with specific embodiments of the above process of thepresent invention:

-   -   at least one adhesion promoter is applied to the substrate        before application of an adhesion primer;    -   at least one adhesion promoter is applied to the substrate as a        mixture with an adhesion primer, therefore at the same time as        the adhesion primer is applied;    -   at least one adhesion promoter is applied to the substrate as a        mixture with the adhesive in the absence of adhesion primer,        therefore at the same time as the adhesive is applied;    -   the adhesion primer and/or the adhesive are applied to the        substrate, the adhesion promoter being incorporated into the        mass of the substrate.

The last three embodiments above may optionally be carried out without acleaning/activation step.

Finally, the present invention relates to a kit for the adhesiveassembly of a thermoplastic elastomer (TPE) polymer substrate S1 toanother substrate S2, said kit comprising:

-   -   an adhesion promoter as defined above, optionally a cleaning        solvent and/or a functional solvent as defined above,    -   at least one of an aqueous adhesion primer intended for coating        S1 and an aqueous glue or adhesive intended for coating the        substrate S1 with adhesive, and    -   at least one of an aqueous or solvent-based adhesion primer        intended for coating the substrate S2 and an aqueous or        solvent-based glue or adhesive intended for coating the        substrate S2 with adhesive.

EXAMPLES

The following examples illustrate the present invention without,however, limiting the scope thereof. In these examples, the followingabbreviations are used:

Substrates

-   -   5533: PEBA of PA12-PTMG type (polyamide-12-polytetramethylene        glycol), sold by the company Arkema under the name “PEBAX®        5533”.    -   7033: PEBA of PA12-PTMG type (polyamide-12-polytetramethylene        glycol), sold by the company Arkema under the name “PEBAX®        7033”.    -   PEBAX® 7033 is harder than PEBAX® 5533.    -   TPE-PU: copolymer comprising polyurethane blocks and polyester        and/or polyether blocks.        Solvent    -   MEK: methyl ethyl ketone    -   BuOH: n-butanol    -   Bu2OH: 1,3-butanediol        Primers    -   W104: water-based primer sold by the company DONGSUNG under the        name “Aquace® W104”.    -   Dply 165: solvent-based primer sold by the company DONGSUNG        under the name “D-Ply® 165”.        Adhesive    -   W01: aqueous adhesive sold by the company DONGSUNG under the        name “Aquace® W01”.

The tests were carried out using the following material:

-   -   press in A524 (WKD 029 setting maximum pressure (indication 78.4        to 147.1 Pa (8 to 15 kg/cm²));    -   Heraeus oven in A524 (FGE 138) setting 70° C., ventilated;    -   ISO 34 punch;    -   pneumatic press for cutting out test specimens.        General Procedure for Assembly

The substrates S1 and S2 are sheets having dimensions of 100×100×1 mm.

(1) Preparation of the Substrate S1

-   -   cleaning (in the comparative examples), with a solvent, a smooth        face of the substrate S1, or cleaning and activating (in the        examples according to the invention), with an adhesion promoter,        a smooth face of the substrate S1;    -   drying for 2 minutes at ambient temperature (unless otherwise        indicated);    -   applying the aqueous primer W104 with a Meyer bar;    -   drying for 5 minutes at 70° C. in a ventilated oven;    -   cooling for 2 minutes at ambient temperature;    -   applying the aqueous adhesive W01 with a Meyer bar;    -   drying for 5 minutes at 70° C. in a ventilated oven.        (2) Preparation of the Substrate S2    -   cleaning a smooth face of the substrate S2 with the MEK solvent;    -   drying for 2 minutes at ambient temperature;    -   applying the Dply 165 solvent-based primer with a brush;    -   drying for 3 minutes at 70° C. in a ventilated oven;    -   cooling for 2 minutes at ambient temperature;    -   applying the aqueous adhesive W01 with a Meyer bar;    -   drying for 5 minutes at 70° C. in a ventilated oven.        (3) Assembly of the Substrates S1 and S2

The two substrates, the surfaces of which have been adhesive-coated, areassembled by pressing at 78.4 Pa (8 kg/cm²) for 15 seconds.

General Procedure for Measuring the Strength of Adhesion or PeelingStrength

Test specimens having dimensions of 100×15×1 mm were cut out with apunch.

The test specimens were conditioned in an air-conditioned room (23° C.,50% RH) for 48 hours.

The peeling test, for measuring the peeling strength, was carried out ona Zwick 1445 (WKM 048) in A12, at 180° C., according to the “Peeling,500N sensor, at 100 mm/min” method, in which the strength is measured asa function of the distance between the jaws of the apparatus(elongation). A regular curve shows a plateau, showing uniform adhesionover the entire test specimen.

Examples or Comparative Examples 1 to 10

The procedure above was applied to various pairs of substrates S1-S2.Table 1 shows the nature of each of these substrates, the type oftreatment of the substrate S1 (cleaning or cleaning and activation), andalso the results obtained in terms of peeling strength.

The term “activation” is intended to mean the application according tothe invention of an adhesion promoter.

TABLE 1 Peeling Cleaning strength Clean- and N/m S1 ing activation S2(kg/cm) Remarks Comp 1 5533 MEK 7033 — test not reproducible irregularadhesion Comp 2 5533 MEK TPE- 4.31 strength PU (0.44) measured afterpressing of pieces at 750 daN Ex 3 5533 1,3- 7033 105.42 regularbutanediol/ (10.75) peeling n-butanol curves (1) Ex 4 5533 1,3- TPE-75.81 butanediol/ PY (7.73) n-butanol (1) Ex 5 (2) 5533 1,3- 7033 116.67regular butanediol/ (11.9) peeling n-butanol curves (1) Ex 6 (3) 55331,3- 7033 between irregular butanediol/ 39.23 peeling n-butanol andcurves (1) 68.64 (4 and 7) Ex 7 5533 1,3- 7033 116.70 very butanediol/(11.9) irregular isobutanol peeling (1) curves Ex 8 7033 carvacrol/ 5533101.01 thymol (4) (10.3) Ex 9 7033 carvacrol 5533 90.22 (9.2) Comp 107033 MEK 5533 0 (1) ratio by volume of 70/30 (2) 1 minute at 70° C.after application of the adhesion promoter (3) 10 minutes at 70° C.after application of the adhesion promoter (4) ratio by volume of 33/66

Examples 3 and 4 compared with comparative examples respectively 1 and2, show the activation of the surface of the substrate S1 when anadhesion promoter is used, making it possible to use an aqueous primerand an aqueous adhesive with a PEBA with excellent adhesion.

Example 5 shows, compared with example 3, that the activation can befurther increased by heating the adhesion promoter.

Example 6, although of the invention since good adhesion is obtained,shows that the activation by heating should be adjusted by those skilledin the art in order to obtain optimized activation.

Example 7 shows, compared with example 3, the effect of the choice ofthe adhesion promoter.

Examples 11 and 12 See FIGS. 1 to 3

Another series of tests was carried out, in which the possibility ofreducing the use of primer or of adhesive was studied.

FIGS. 1, 2 and 3 represent schematically the multilayer structure ofexample 3, example 11 and example 12, respectively.

In example 11, carried out on the model of example 3, during thepreparation of the substrate S1, no primer was applied to said activatedsubstrate S1, unlike said example 3. The adhesive W01 is subsequentlyapplied directly to the activated substrate S1. The adhesive-coatedsubstrate S1 is then obtained. The preparation of the substrate S2 hasalready been described above.

In example 12, carried out on the model of example 3, during thepreparation of the substrate S1, the primer W104 was applied to theactivated substrate S1, but no adhesive was subsequently applied, unlikesaid example 3. The adhesive-coated substrate S1 is then obtained. Thepreparation of the substrate S2 has already been described above.

The substrates thus prepared were assembled with the substrate S2 withthe same general assembly procedure described above. The resultsobtained are very good: peeling strength >48.4 N/cm (8 kg/cm) andregular curves.

1. An adhesive assembly comprising at least two layers of substrate S1and S2 bonded by means of at least one aqueous adhesive system, at leastone of the substrates being a thermoplastic elastomer polymer (TPE)having been activated by an adhesion promoter which is a solventselected from the group consisting of butanediols, 1,3-butanediol,1,4-butanediol, metacresol, carvacrol, glycerol, glycols, butyl glycol,butyl diglycol, butanols, n-butanol, isobutanol, benzyl alcohol,limonene, and mixtures thereof, wherein the thermoplastic elastomerpolymers of the substrate S1 are chosen from copolymers comprising softpolyester or polyether blocks and comprising hard blocks, wherein saidhard blocks are chosen from polyamide (PA), polyurethane (PU) andpolyester; wherein S2 is either a thermoplastic elastomer polymer chosenfrom copolymers comprising soft polyester or polyether blocks andcomprising hard blocks, wherein said hard blocks are chosen frompolyamide (PA), polyurethane (PU) and polyester—or else S2 is selectedfrom the group of polymers and copolymers consisting of polyolefins,polyamines, polyamides (PA), polyesters (PES), polyethers (PE),polyester ethers, polyimides, polyamideimides, polycarbonates, phenolicresins, crosslinked or noncrosslinked polyurethanes (PU), PU foams,polyimides, poly(ethylene/vinyl acetate)s, natural or syntheticelastomers, polybutadienes, polyisoprenes, styrene-butadiene-styrene(SBS), styrene-butadiene-acrylonitrile (SBN), polyacrylonitriles,natural or synthetic fabrics, fabrics made of organic polymer fibers;fabrics made of polypropylene, polyethylene, polyester, polyvinylalcohol, polyvinyl acetate, polyvinyl chloride or polyaramid fibers;fabrics made of glass fibers, fibers made of carbon fibers, leather,paper, glass, wood and cardboard.
 2. The adhesive assembly of claim 1,wherein said adhesive assembly comprises a shoe sole.
 3. The adhesiveassembly of claim 1, wherein the adhesion promoter(s) are incorporatedinto the aqueous adhesion primer, into the aqueous adhesive, and/or intothe substrate S1 by bulk incorporation during its transformation.
 4. Theadhesive assembly of claim 1, wherein the adhesive system is of thetwo-component polyurethane type.
 5. The adhesive assembly of claim 1,wherein the copolymers in substrate S1 comprise polyamide blocks andpolyether blocks (PEBA) blocks, of the polyether ester amide type. 6.The adhesive assembly of claim 1, wherein the substrate S1 is a PEBA andthe adhesion promoter is butanediol.